An investigator is planning a clinical trial of three treatments, two investigational treatments (A and B) versus a standard treatment (S) for carcinoma of the lung. Twenty-eight hundred (2,800) patients are to be randomized in a 1:1:1.5 allocation ratio. The investigators plan to use a stratified design with strata corresponding to 4 prognostic factors: sex, age (<60, 60+ years), prior therapy (yes, no), and stage of disease (I, II, III)

A) .If a separate randomization schedule is prepared for each stratum, how many schedules will have to be prepared for this study?

b) If a single block size is to be used to prepare each schedule with block randomization, what is the smallest block size that can be used?